It is known in the metal working art to provide hold down tools between the faces of a pair of vise jaws for engagement with a workpiece by providing a "pinching down" action on the workpiece to ensure that the workpiece is held tightly on the parallels or work supporting surface of the vise. Examples of such prior art hold down tools are shown in U.S. Pat. Nos. 1,125,207; 1,242,182; 1,951,869; 2,014,967; 2,124,200; 2,477,297; 2,740,310 and 3,020,041.
The prior art hold down tools disclosed in the aforementioned patents operate most efficiently when used in pairs, and a disadvantage of these prior art hold down tools is that they are awkward and difficult tools to use because the operator must use two hands to align and position a pair of such prior art hold down tools, and call for assistance from another party to tighten the vise or other clamping means with which the hold down tools are used.
Some of the prior art hold down tools employ additional supports, and an example is the hold down tool shown in the aforementioned Larsen U.S. Pat. No. 2,740,310. The pair of hold down tools shown in the Larsen patent are restrictive and awkward in use because of the space required for the separately attached magnets for each of the pair of hold down tools.